Automatic adjustable torque wrench



Get. 31, 1950 M. A, BARKER ETAL 2,527,517

AUTOMATIC ADJUSTABLE TORQUE WRENCH Filed Sept. 11, 1947 I ling HM l )1ventor Melvin A. fiarke Howard James F/nch Arthur J; Rooks Ewan/EhPatented Oct. 31, 1950 AUTOMATIC ADJUSTABLE TORQUE WRENCH Melvin A.Barker and Howard James Finch, De-

troit, and Arthur J. Rooks, Hamtrarnck, Mich.

Application September 11, 1947, Serial No. 773,468

Claims.

This invention relates to novel and useful improvements in an automaticadjustable torque wrench and more specifically relates to an improvedconstruction and means for selectively adjustin the torque at which aclutch embodied in the wrench releases, to thereby regulate withexactness the force in inch pounds applied to a nut or bolt.

The principal object of this invention is to provide a novel andimproved adjustable clutch mechanism embodied in a torque wrench whichshall be extremely compact, efficient in operation, of simplifiedconstruction and which may be readily adjusted to apply anypredetermined torque or force to a nut or bolt.

A further object of the invention is to provide a mechanism according tothe preceding objects which may be equally embodied in a wrench operablemanually or from a source of power.

Yet another important purpose of the invention is to provide a tool ofthe character set forth above wherein there is provided an improvedmeans for adjusting the spring tension upon the clutch member tooccasion slippin in the clutch at a predetermined torque, together witha combined coupling means and torque indicating adjustment means.

These, together with various ancillary objects of the invention whichwill later become apparent as the following description proceeds, areattained by this device, a preferred embodiment of which has beenillustrated by way of example only in the accompanying drawings,wherein:

Figure 1 is an elevational View showing the improved wrench embodyingthe invention;

Figure 2 is a vertical longitudinal sectional view taken substantiallyupon the plane of the section line 2-2 of Figure l and showing theinterior construction of the device; and,

Figures 3-7 are horizontal sectional detail views taken substantiallyupon the plane indicated by the section lines 3-3, 44, 55, 6-6 and 1-1of Figure 2.

. Referring now more specifically to the accompanying drawings; whereinlike numerals designate similar parts throughout the various views, theimproved wrench is shown as comprising an upper body It! having atapering operating shank l2, and a lower body I 4 having a reduced,bored shank portion I6 at the lower end thereof. The shank I6 isprovided with an enlarged internal annular chamber [8, from whichextends a polygonal shaped axial bore 20 which may be hexagonal asshown. Slidably and not rotatably received in the bore 20 is thereduced, correspondingly shaped inner extremity 22 of a shank 24 whoseoutermost extremity 26 is of square cross section for detachablyreceiving a wrench socket 28 secured thereto and by a set screw 30 orany other suit-able detachable securing means. As will readily beunderstood, it is contemplated that a plurality of different size wrenchsockets 28 may be selectively positioned upon the extremity 26. Thepolygonal shaped inner extremity 22 of the shank 24, is provided with anannular groove 32 by means of which the shank is retained in the bore ofthe shank I6, by means of a laterally positioned inwardly extending setscrew 34 whose inner extremity engages the groove 32.

The bodies l0 and M are provided with complementary and adjacentchambers 36 and 38 respectively within which are respectively secured amale clutch member 40 slidably but not rotatably received in the chamber36 as by cooperating key 42, this clutch member having a lower conicaltapering clutch surface 44, which as shown in Figure '7 is provided withlongitudinally extending imbedded Wear inserts 50.

Within the chamber 38 of the lower body member I4, is rigidly secured aremovable female clutch insert 48 having a conical shaped clutch surface46 frictionally engaging the similarly shaped conical clutch surface 44with its friction inserts 50.

The conicities of the cooperating male and female clutch elements aresuch that as the members are forced towards each other, their frictionalengagement increases, whereby a greater torque may be transmitted fromone to the other by relative rotation of the shanks l2 and IS.

A coupling gland 52 engages an annular shoulder upon the lower body l4and is provided at its outer extremity with an internally threadedportion 54 embracing and threadingly engaging corresponding threads 56on the lower outer eX- tremity of the body portion l0. As will readilybe seen, by screwin the coupling gland upon the body ID, the two clutchbodies will be drawn forth together, and they may be locked in desiredadjusted position by means of a set screw 58 depending through thecoupling gland 52 and engaging an area of the lower circumference of thebody It).

As shown in Figures 1 and 2, the upper extremity of the coupling gland52 is conically tapered as at 60 and is provided with suitable indicia62 registerable with corresponding indicia 64 carried upon the adjacentsurface of the upper body member ID, to thereby indicate 3 the relativeportional capacity of the clutch members in inch pounds or othersuitable torque calibrated indicia.

As shown in Figure 2, a coil spring 66 is received within the chamber 36of the upper body member ID, and abuts against the bottom of saidchamber and extends into and engages the bottom of a recess extendingaxially into the male clutch member 40, to thereby urge the latterdownwardly and outwardly from the upper body member ID and into thefemale clutch member 48 of the lower body member l4, Obviously, byadjusting the coupling gland 52 the lower body member and the femaleclutch member may be urged upwardly against the clutch surface of thedownwardly extending male clutch member against the opposition of spring66, and the above mentioned indicia 62 and 63 may be so calibrated as toindicate when any desired tension has been applied against the spring 66and any desired torque may be carried by the cooperating clutch members.

From the foregoing, it is believed that the manher of operating andconstructing the device will be readily understood. In operation, theshank [2 may be received in any suitable power operating means wherebythe wrench may be operated automatically from the power source, or amanual operating means may be applied thereto as desired. Any suitablesize of socket 28 may be secured to the shank 24 extending from thelower end of the wrench, for adapting the latter to any particular workdesired. When the wrench has been applied, and the combined couplinggland 52 and torque adjusting means has been satisfactorily manipulated,and locked in its adjusted position by means of the set screw 58, therotation of the shank I2 is transmitted through the keys 42 to the maleclutch member 40 rotating the latter and by means of the frictionalengagement between the'cooperating surfaces 44 and 46, causing rotationof the female clutch member 48 and subsequently of the tool socket 28.This rotation continues until the resistance of the nut or bolt engagedby the socket 28 is sufficient to reach the desired torquefor which thetool is set, whereupon the friction between the surfaces 44 and 46 isovercome and further rotation of the handle or shank I2 is insufiicientto cause rotation of the socket 28.

Obviously the parts may be so calibrated that it will be possible to setthe device for maintaining any desired torque transmission by the clutchto the socket 28.

Since numerous modifications will readily occur to those skilled in theart after a consideration of the foregoing specification andaccompanying drawings, it is not intended to limit the invention to theexact construction shown and described, but all suitable modificationsand equivalents may be resorted to falling within the scope of theappended claims.

Having described the invention, what is claimed as new is:

1. In a torque wrench, a pair of relatively rotatable bodies havingcomplementary and ad jacent chambers, cooperating male and female clutchmembers disposed in said chambers, spring means disposed in one of thechambers for urging said male clutch member into engagement with thefemale clutch member and means for rotatably securing said bodiestogether and for regulating said spring means adjustably embracing eachof said bodies and concentrically disposed about the chambers thereof toprovide a predetermined and adjustable torque release for said clutchmembers.

2. The combination of claim 1 wherein one of said clutch members isnon-rotatably but axially adjustably secured in its chamber.

3. The combination of claim 1 wherein one of said clutch members isrigidly secured in its chamber.

4-. In a torque wrench, a driving member having a tapered shankterminating in an enlarged chamber, a driven member having a toolreceiving shank and a chamber disposed complementary and adjacent tosaid chamber of the driving member, cooperating male and female clutchmembers disposed in said chambers, said male clutch member beingnon-rotatably but axially adjustably disposed within the driving memberchamber, resilient means disposed in the chamber of the driving memberand bearing against the male clutch for urging the same into engagementwith the female clutch, and means embracing both of said bodies andconcentrically disposed about the chambers for rotatably securing thebodies together and for regulating said resilient means to provide anadjustable torque release for said clutch members,

5. In a torque wrench, a driving body and a driven body, said bodieshaving complementary and adjacent chambers, a fixed female clutch memberdisposed in one of said chambers, a nonrotatably and axially adjustablemale clutch member disposed in the other of said chambers and adaptedfor cooperation with the female clutch member, resilient means disposedin one of said chambers and bearing against the male clutch member forurging the same into driving engagement with the female clutch member, amember embracing both of said bodies and having screw-threadedengagement of one of said bodies for rotatably securing said bodiestogether and regulating the resilient means.

MELVIN A. BARKER. HOWARD JAMES FINCI-I. ARTHUR J. ROCKS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 923,043 Gulick May 25, 19091,002,310 Procunier Sept. 5, 1911 1,669,862 Christianson et a1. May 15,1928 2,268,869 Given Jan. 6, 1942

